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Date: Tue, 23 Apr 2013 10:42:45 +0530 From: Sourav Poddar <sourav.poddar@...com> To: Grygorii Strashko <grygorii.strashko@...com> CC: <gregkh@...uxfoundation.org>, <tony@...mide.com>, <rmk+kernel@....linux.org.uk>, <khilman@...aro.org>, <linux-serial@...r.kernel.org>, <linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org> Subject: Re: [PATCHv2 2/5] driver: serial: omap: prevent runtime PM for "no_console_suspend" Hi Grygorii, On Monday 22 April 2013 08:18 PM, Grygorii Strashko wrote: > On 04/22/2013 04:43 PM, Sourav Poddar wrote: >> The driver manages "no_console_suspend" by preventing runtime PM >> during the suspend path, which forces the console UART to stay awake. >> >> Signed-off-by: Sourav Poddar <sourav.poddar@...com> >> --- >> drivers/tty/serial/omap-serial.c | 5 ++++- >> 1 files changed, 4 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/tty/serial/omap-serial.c >> b/drivers/tty/serial/omap-serial.c >> index 08332f3..640b14e 100644 >> --- a/drivers/tty/serial/omap-serial.c >> +++ b/drivers/tty/serial/omap-serial.c >> @@ -1582,7 +1582,7 @@ static int serial_omap_runtime_suspend(struct >> device *dev) >> struct uart_omap_port *up = dev_get_drvdata(dev); >> struct omap_uart_port_info *pdata = dev->platform_data; >> - if (!up) >> + if (!up || (!console_suspend_enabled && uart_console(&up->port))) >> return -EINVAL; > Hi Sourav, > No ) You will block Runtime PM for console UART forever, but instead > it need to be blocked only during suspend - autosuspend should > continue working. > But this will be not easy, again, - > because System suspend isn't synchronized with Runtime PM (I mean, > serial_omap_suspend/resume() may be called from one thread and > serial_omap_runtime_suspend/resume() from another at same time). > And now, serial_omap_suspend() callback is the only one place where you > can detect that system is going to sleep. > Yes, got this point. As Kevin has already suggested a way to get around this, I will fix this portion in the next version. > Personally, i don't believe in such approach (my experiences from K3.4 > said me > that there will be more problems than benefits). > > And, I like combination of "no_console_suspend" in bootargs + > "ti,no_idle_on_suspend" for console UART in DT, because 1) it's debug > option and 2) until > smth. will be decided about OMAP OCP Bus it can be used. > > It's just my opinion. > > Regards, > -grygorii >> if (!pdata) >> @@ -1614,6 +1614,9 @@ static int serial_omap_runtime_resume(struct >> device *dev) >> int loss_cnt = serial_omap_get_context_loss_count(up); >> + if (!console_suspend_enabled && uart_console(&up->port)) >> + return -EINVAL; >> + >> if (loss_cnt < 0) { >> dev_err(dev, "serial_omap_get_context_loss_count failed : >> %d\n", >> loss_cnt); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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